Web02 RAID and MySQL problems (resolved)

Between 05:46 AM Pacific time and 06:58 AM Pacific time (December 29 2017) some Web sites on our web02 server were inaccessible. This was caused by the failure of a disk in the RAID array. When the disk failed MySQL continued to read corrupted data from it’s file cache rather than using another disk in the RAID array. The cache has now been cleared and the server restarted. This was unrelated to the problems on our web13 server earlier in the day.